Fungal meningitis refers to meningitis caused due to a fungal infection.
The clinical features of fungal meningitis similar to any other cause of meningitis. It can present with fever, neck stiffness, nausea, photophobia, vomiting, headache and mental status changes  . Fungal meningitis is non-contagious as compared to bacterial and viral meningitis that are known to be contagious. Fungal meningitis can occur only due to hematogenous or contiguous spread from a local site of infection to the CNS  . It is typically found in immunocompromised hosts, although the causitive pathogen can vary according to the local environment  .
Clinical features of fungal meningitis are indistinguishable from other causes of meningitis and hence require various laboratory tests to obtain a diagnosis. The presenting signs and symptoms may consist of the following:
For any case with suspected meningitis, blood and cerebrospinal fluid (CSF) samples are sent for laboratory evaluation urgently, since the treatment varies according to the causitive agent. The tests include:
CSF analysis usually exhibit decreased glucose levels, high protein levels and a lymphocytic pleocytosis in the range of 10-200 cells/µl for most fungal causes of meningitis, including Cryptococcosis. Rarely, cases of C. immitis have been associated with eosinophilic pleocytosis.
These can be used as a mode of obtaining a definitive diagnosis for certain fungal pathogens, such as H. capsulatum, B. dermatitidis, C. immitis and Candida spp.
The detection fungal antigens is frequently used for diagnosing fungal meningitis, especially for histoplasmosis. Serology is helpful for diagnosing the fungi that are difficult to culture. However, in certain cases such as B. dermatitidis, serology is not considered conclusive since a negative test fails to rule out the diagnosis.
The treatment for fungal meningitis usually consists of high-dose anti-fungal medications administered intravenously (IV) in an inpatient setting. The treatment duration is variable, and depends upon factors such as the immune status of the patient and the pathogen involved  . Patients diagnosed with comorbidities such as diabetes, cancer and AIDS that compromise the immune system usually have a prolonged course of treatment  .
It is known to be an opportunistic infection in individuals diagnosed with HIV/AIDS. Treatment consists of amphotericin B (0.7-1 mg/kg/day IV) for a minimum of 2 weeks. Flucytosine (100mg/kg by mouth in 4 divided doses) can also be added. Liposomal amphotericin B (amphotericin B liposome 3-4 mg/kg/day or amphotericin B lipid complex 5 mg/kg/day) may be considered in cases with predisposition to or pre-existing renal dysfunction. The consolidation phase of the therapy involves administering fluconazole (400 mg/day) for 8 weeks. Itraconazole can be used as an alternative if the patient is not able to tolerate fluconazole. The maintenance phase of the therapy consists of fluconazole 200 mg/day to prevent relapse. Fluconazole is known to be superior to itraconazole and amphoterecin B (1 mg/kg once a week), both, for preventkion of relapse. Cases with HIV/AIDS have a higher risk of relapse.
In places with limited resources, fluconazole and amphotericin B are considered as optimal for treating HIV/AIDS associated acute cryptococcal meningitis. It is recommended that the administration linked to healthcare services in countries with inadequate health facilities should consider providing drugs such as flucytosine that are often unavailable at these places, to optimize HIV treatment programs .
C. immitis associated meningitis is treated with fluconazole (400 mg/day by mouth). Some practitioners prefer initiating the treatment with a higher dose of fluconazole (up to a maximum of 1000 mg/day) or intrathecal amphotericin B and fluconazole combination. The efficacy of itraconazole (400-600 mg/day) is comparable to the aforementioned options. Miconazole IV may also be considered. C. immitis meningitis often requires lifelong treatment.
The preferred option for treating meningitis secondary to H. capsulatum is liposomal amphotericin B, dosage being 5 mg/kg/day IV, with a total of 175 mg/kg over 4-6 weeks). This is followed by a minimum 1 year therapy with itraconazole (200-300 mg BID to TID) till the abnormalities in CSF are resolved and/or histoplasma antigen levels return to normal reference range. The level of itraconazole in blood must be monitored periodically to ensure adequate absorption of the drug.
The drug of choice for the treatment of meningitis due to Candida is amphotericin B (0.7 mg/kg/day). Another drug, flucytosine (25 mg/kg QID, dosage adjusted to obtain serum level of 40-60 µg/ml) is often added to amphotericin B. Suppresive or follow-up therapy usually involves using azoles.
There is a high risk of relapse in candidal meningitis. Treatment is usually continued for four weeks after resolution of symptoms, however, there are no specific guidelines for the duration of the treatment. If candidal meningitis has occured secondary to neurosurgical procedures, removal of any implanted prosthetic materials, such as ventriculoperitoneal shunts, that are suspected of being a nidus for infection should be considered.
The best initial therapy is liposomal amphotericin B, and itraconazole (200 mg BID) as a step-down once the patient responds to amphotericin B. The total duration of therapy should be a minimum of 12 months. Itraconazole can also be used as lifelong suppression therapy, but only after initial therapy with amphotericin B. Itraconazole is more effective against S. schenckii that fluconazole.
According to the current guidelines from CDC, liposomal amphotericin B or voriconazole IV are the most optimal options for treating E. rostratum .
Fungal meningitis has been associated with frequent treatment related complications, neurological sequelae and a high rate of mortality . It often requires close monitoring and counselling for treatment adherence due to high rates of relapse associated with early termination of treatment.
The most frequently encountered pathogen that causes fungal meningitis is Cryptococcus neoformans. It commonly inhabits the soil and is widely found in the environment. Infection occurs through inhalation of air-borne spores. Interestingly, the inhalation of spores does not result in an infection in healthy hosts, rather only those individuals who are immunocompromised, as they are unable to prevent the survival and growth of the fungal spores . C. neoformans infection can present as cutaneous lesions, pulmonary involvement and central nervous system (CNS) disease, including meningitis .
C. neoformans is frequent fungal cause of meningitis in immunocompromised hosts. In Africa, it is one of the more common causes of meningitis in adults. Likewise, certain fungal pathogens are endemic to specific parts of United States. For instance, Histoplasma capsulatum is found individuals with a history of contact with bat and bird droppings, typically in Midwestern part of United States. On the other hand, Coccidioides infection, also known as valley fever, is more prevalent in the Southwest region and usually is found in Filipinos, African Americans, immunocompromised hosts and women in third trimester of pregnancy.
The blood-brain barrier formed by meninges protects the brain from the components of immune system in the blood. In situations where the blood-brain barrier is disrupted, such as meningitis, pathogens can disseminate to the brain and may spread rapidly due to partial isolation from the immune system. As the body develops an immune response to the infection, there is inflow of fluid, white blood cells (WBCs) and other inflammatory mediators due to the increased permeability of blood vessels in the meninges and brain. This may lead to cerebral edema that will lead to symptomatic worsening of the patient due to diminished blood flow to various parts of the brain .
Fungal meningitis is a non-contagious disease. It may occur due to hematogenous dissemination or by contiguous spread from a local infection. Medications such as steroids, anti-TNF (tumor necrosis factor) agents and those prescribed status-post organ transplantation, are known to weaken the immune system and lead to an increased risk for developing fungal meningitis.
Cryptococcosis occurs due to inhalation of soil that is contaminated with bird droppings. Histoplasma is prevalent in places like caves with bat and bird droppings, typically in the Ohio and Mississippi river valleys. Blastomyces is commonly found in soil that has decaying organic matter, and is mostly prevalent in the northern Midwest region of United States. Coccidioides is endemic to Southwest United States, along with certain parts of South and Central Americas. Candidiasis is usually acquired in an inpatient setting. The route of transmission for most fungal infections is usually thorough inhalation of spores. Meningitis occurs when the fungal infection spreads to the brain.
Avoidance of the specific environments that are most likely to have fungal spores is the best way to prevent infection. Immunocompromised individuals should be advised to avoid dusty environments, digging activities and bird droppings, especially if they dwell in a region with prevalence of Histoplasma, Blastomyces or Coccidioides.
Meningitis is defined as a clinical syndrome that involves inflammation of the meninges. Fungal meningitis occurs usually due to dissemination of a hematogenous fungal infection to the spinal cord. It is a rare cause of meningitis and frequently occurs in immunocompromised states such as cancer and HIV infection.
Fungal meningitis is a rare disease. It occurs due to spread of a fungus from the blood to the brain and spinal cord. The clinical signs and symptoms that you may experience are similar to those from meningitis due to any other cause. These include headache, nausea, vomiting, stiffness of the neck, fever and inability to tolerate bright light. Unlike several other forms of meningitis, fungal meningitis is a non-contagious disease and occurs only if the infection enters the blood or gains direct access to the brain and spinal cord from a nidus close to these organs. The treatment for fungal meningitis involves the use of high dose anti-fungal drugs, that are given intravenously for several months. The duration of receiving the treatment, however, varies depending on how good your immune system is working and the type of fungus causing your condition.